The new US Secretary of State has said the greatest challenge to American foreign policy is actually at home with Congressional spending cuts, rather than China or the Middle East.

In his first major speech as the top US diplomat, John Kerry focused on the latest fiscal showdown between the White House and Congress and the threat of massive automatic spending cuts on March 1.

He said his country needed to resolve its economic issues, otherwise it would be "hard" to tell other nations to do the same.

Speaking at the University of Virginia, the Democrat said legislators needed to avoid "senseless cuts" and he called the budget impasse in Congress a threat.

Automatic spending cuts would jeopardise $2.6bn (£1.7bn) in aid, security assistance and other international programmes, according to his department.

He declared that "deploying diplomats today is much cheaper than deploying troops tomorrow", adding: "In many ways the greatest challenge to America's foreign policy today is in the hands not of diplomats, but of policymakers in Congress."

Mr Kerry went on: "My credibility as a diplomat working to help other countries create order is strongest when America at last puts its own fiscal house in order - and that has to be now."

He cited the adage that "we can't be strong in the world unless we are strong at home".

And he added: "It is hard to tell the leadership of any number of countries that they must resolve their economic issues if we don't resolve our own."

Some $85bn (£55bn) of automatic spending cuts are set to begin at the start of next month, with more than $1trn (£654bn) in cuts over the next decade.

Image Caption:John Kerry replaces Hillary Clinton

President Barack Obama and Republican House Speaker John Boehner both agree the federal budget needs that level of deficit reduction and more, but sharply disagree over how to achieve it.

The president has called on House Republicans to drop their resistance to tax increases and steer the country away from the budget "meat cleaver".

But Mr Boehner reminded the president the automatic cut idea was originally offered by the White House during the debt-ceiling talks of 2011. He said Congress "reluctantly accepted the president's demand" and claimed it was now up to Mr Obama to find a solution.

Mr Kerry was sworn in earlier this month, replacing Hillary Clinton. His speech in Virginia comes days before he embarks in his first overseas trip as Secretary of State.

During the trip Mr Kerry will visit nine nations, including in the Middle East, but will bypass Israel and the Palestinian territories.

State Department spokeswoman Victoria Nuland said Washington was waiting for Israeli political parties to form a new government after their recent election.

Conflicts in Syria, Mali and Afghanistan are expected to top the agenda in many capitals.

Mr Kerry, 69, is a decorated Vietnam veteran and long-serving senator who has chaired the Foreign Relations Committee for several years. He was the Democratic presidential candidate in 2004, when he lost to George W Bush.